There have been a variety of proposed dyes for use as polymerizable compounds to affect the colorization of optical plastics for lenses and ocular devices. Most of these relate to various diphenyl azo or triphenyl diazo compounds. These generally claim to provide UV protection as well as blue light blocking capability because of their yellow or orange-yellow color. Because the human crystalline lens is pale yellow in color in young people and a brownish yellow color in older people, these dyes serve the purpose of providing UV protection in addition to blue light filtering capability.
In addition, U.S. Pat. No. 6,825,975 (Gallas) discloses a light filter prepared by oxidatively polymerizing 3-hydroxykynurenine to form complex visible light absorbing compounds that have a very broad absorption spectrum that is very different from 3-hydroxykynurenine. Moreover, this system is limited to oxidatively polymerized 3-hydroxykynurenine and does not provide versatility and tunability. Moreover, this system only provides blue light filtering capability. The amino acid functionality is still present.
A need exists to provide, for example, more discrete structures which are easier to make and provide better and more versatile performance which can be tuned to particular applications.